1. Field of the Invention
The present invention relates to an optical module holder, an optical module, and an optical connector. In particular, the present invention relates to an n optical module holder, an optical module, and an optical connector that are suitable for attaching an optical element onto the optical module holder.
2. Description of the Related Art
An optical module for optically coupling a photoelectric conversion element and an optical fiber has been used for optical communication performed via the optical fiber. The photoelectric conversion element includes at least one of a light-emitting element or a light-receiving element. An optical component called an optical module holder is used during manufacture of an optical module such as this.
As shown in FIG. 29, an optical module holder 1 includes a lens 3, a cylindrical photoelectric conversion element attaching section 5, and a cylindrical optical fiber attaching section 6. The lens 3 is used to optically couple a photoelectric conversion element and an end section of an optical fiber. The photoelectric conversion element attaching section 5 extends towards one side (upper area in FIG. 29) in an optical axis direction (vertical direction in FIG. 29) of the lens 3, in relation to the lens 3. The optical fiber attaching section 6 extends towards another side (lower area in FIG. 29) in the optical axis direction (vertical direction in FIG. 29) of the lens 3, in relation to the lens 3.
In the optical module holder 1 such as this, the photoelectric conversion element is attached to an inner circumferential surface of the photoelectric conversion element attaching section 5 through adhesion using an adhesive, thereby configuring the optical module.
During the manufacture of an optical module such as this, before the photoelectric conversion element is attached to the optical module holder 1, a centering operation has conventionally been performed for adjusting an attachment position of the photoelectric conversion element to optimize a positional relationship between the lens 3 and the photoelectric conversion element.
An ultraviolet (UV) curable adhesive that hardens as a result of irradiation by ultraviolet rays has conventionally been used as the adhesive used in the attachment of the photoelectric conversion element accompanying the centering operation such as that described above. When the UV curable adhesive is used, the centering operation can be smoothly performed even when the UV curable adhesive remains applied onto the inner circumferential surface of the photoelectric conversion element attaching section 5, as long as the UV curable adhesive is not irradiated with the ultraviolet rays.
In the manufacture of the optical module involving the centering operation such as that described above, first, as shown in FIG. 30, a UV curable adhesive 7 is applied onto a predetermined application surface 5a on the inner circumferential surface of the photoelectric conversion element attaching section 5. The photoelectric conversion element 1 is then inserted into the photoelectric conversion element attaching section 5. Depending on photoelectric conversion element and photoelectric conversion element attaching section types, the UV curable adhesive can be applied after the photoelectric conversion element is inserted into the photoelectric conversion element holder.
The photoelectric conversion element 11 shown in FIG. 30 uses a so-called controlled area network (CAN) package system in which an element body (a light-emitting section 8 in FIG. 30) is enclosed within a package 10 that has a window 9. In a state in which the photoelectric conversion element 11 is inserted within the photoelectric conversion element attaching section 5, an outer circumferential surface of the package 10 is surrounded by the inner circumferential surface of the photoelectric conversion element attaching section 5.
Therefore, in the state in which the photoelectric conversion element 11 is inserted within the photoelectric conversion element attaching section 5, the UV curable adhesive 7 is present between the outer circumferential surface of the package 10 and the application surface 5a on the inner circumferential surface of the photoelectric conversion element attaching section 5.
At this time, the UV curable adhesive 7 is not yet irradiated with the ultraviolet rays. The UV curable adhesive 7 still retains fluidity. Therefore, the centering operation can be performed by, for example, the photoelectric conversion element 11 being rotated around an optical axis of the lens 3.
After the attachment position of the photoelectric conversion element 11 is decided by the centering operation, as shown in FIG. 31, the UV curable adhesive 7 is irradiated with the ultraviolet rays from outside of the photoelectric conversion element attaching section 5. As a result, the UV curable adhesive 7 is hardened.
As a result, the UV curable adhesive 7 achieves adhesive force. The photoelectric conversion element 11 is temporarily fixed at a post-centering-operation position by the adhesive force of the UV curable adhesive 7.
After being temporarily fixed, the photoelectric conversion element 11 temporarily fixed at the post-centering-operation position is firmly adhered at the position by an adhesive, such as an epoxy resin, having stronger adhesive force than the UV curable adhesive 7.
As a result of the photoelectric conversion element 11 being attached to the photoelectric conversion element attaching section 5 in this way, the optical module can be achieved.
Patent Literature 1 and Patent Literature 2, for example, disclose conventional technologies for configuring an optical module using a UV curable adhesive.
Patent Literature 1: Japanese Patent Laid-open Publication No. Heisei 8-220386
Patent Literature 2: Japanese Patent Laid-open Publication No. 2002-43675
However, conventionally, when a material having low ultraviolet ray transmittance is used as a material for forming the, photoelectric conversion element attaching section 5, a large amount of ultraviolet rays cannot be simultaneously irradiated onto the UV curable adhesive 7 applied onto the application surface 5a of the photoelectric conversion element attaching section 5 by the ultraviolet rays being transmitted through the photoelectric conversion element attaching section 5 from outside of the photoelectric conversion element attaching section 5.
As a result, conventionally, time required from when the irradiation of the UV curable adhesive 7 by the ultraviolet rays starts until when the UV curable adhesive 7 hardens (referred to, hereinafter, as hardening time) increases. Mass productivity of the optical module and the optical connector including the optical module cannot be improved.